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P. F. HOLMGREN. VIBRATING PISTON STEAM ENGINE.

No. 440,569. Patented Nov. 11, 1890.

PETER F. HOLMGREN, OF BROOKLYN, NEW YORK, ASSIGNOR OF ONE-HALF TO JOI-IN CARLSON, OF SAME PLACE.

VIBRATING-PISTON STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 440,569, dated November 11, 1890.

Application filed February 1l, 1890. Serial No. 339,976. (No model.)

To all whom it may concern:

Be it known that I, PETER F. HOLMGREN, of the city of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Vibrating- `Piston Engines; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, making a part. of this specification.

My invention relates to the class of engines having vibrating pistons, and has for it-s ob- Aject to provide at a low cost a simple compact single-acting compound engine.

It consists in the novel combination and arrangement, substantially as hereinafter described and claimed, of the two single-acting pistons of unequal area with a single crankshaft mounted parallel with the axes of the pistons within the same casing, and with sectoral piston-chambers having a connectingpassage controlled by suitable valves, by means whereof the exhaust-steam from the high-pressure piston-chamber is delivered to the low-pressure piston-chamber.

In the accompanying drawings, Figure lis an irregular vertical section through the casing of the engine in line y y of Fig. 2, showing its working parts in elevation; and Fig. 2 is a vertical section in line a: 0c ot' Fig. l.

Similar letters indicate like parts in both figures.

A A represent the two vibrating pistons of the engine. These pistons severally radiate from hubs or collars E E', which encircle and are pivoted upon axial shafts B B mounted and fixed at their ends in the casing C. The hub of each piston is partially embraced longitudinally by a partition D, interposed between the two hubs, and which connects the two end plates of the-casing. The joint between each hub or collar and the partition D is made tight by means of a suitable packing-strip a, as shown in Fig. 2. .Each piston vibrates in a sectoral chamber F F', formed to inclose it in the casing C, and each of said chambers F F is open at one end, the piston moving therein being made to work up closely against the partition-plate G, which closes its opposite end. The inner or end plate in each piston-chamber is provided with a port formed therein, and which is governed by a rotating valve through which the steam admitted to the piston is admitted and exhausted.

The valve H, which controls the steam-port for the piston-chamber F of least area, is made to establish communication alternately with a steam-passage I in the casing, to which the supply-pipe from the boiler is connected, and with an exhaust-passage leading to the larger piston-chamber F. This passage is enlarged intermediate the two chambers, so as to form a middle steam-chamber J between them.

The valve H', controlling the steam-port in the larger piston-chamber F', is made to communicate alternately with said intermediate steam-chamber J and with an exhaust-passage K, leading out from the engine.

The crank-shaft L to be driven by the pistons is mounted beneath them, and the crank L thereon revolves in a chamber M, formed in the lower part of the casing as an extension of the open ends of the two piston-chambers F F to communicate freely therewith. Each piston is connected with the one crank'L on the shaft L by means of coupling-rods N N, and the connection is so adjusted that the one piston shall have a slight lead over the other, as shown in Fig. 2, so that they may not be both upon a dead-center at the same time.

To prevent an accumulation of the water in front .of the piston in each chamber due to a condensation of steam, I insert in each piston a valve S, opening outward, and which is closed `by a spring T-of sufficient power to resist the highest steam-pressure which may be exerted upon the piston. The crank L is preferably counterbalanced by the extension O O of its two radial arms on the opposite side of the shaft.

The steam-valves H H are actuated from an eccentric P on the main shaft L, each by an independent couplingr0d Q, extending to a rocking arm R, which is in turn coupled to the shaft carrying the valve, the rods being so adjusted that one of the valves H shallv have a lead over the other H.

The crank-chamber M may be partially filled with oil, so that the crank will at each revolution dip therein, and thereby insure a thorough and constant lubrication of the pistons and other working parts of the engine.

In the operation of the engine steam is ad- IOO mitted at high-pressure through the valve H, against the piston A of least area, and will drive it forward at full pressure to the end of its stroke, whereupon, by the movement of the valve H, produced automatically oy the action of the eccentric P on the crank-shaft, the valve will operate to cut off the supply of steam and will open the exhaust-passage from the piston-chamber into the intermediate steam-chamber J, so that as the piston A makes its return-stroke the steam will exhaust from before it into said chamber J. While the high-pressure piston A is making its 'forward stroke the valve H will have opened the port between the steam-chamber J and the low-pressure piston-chamber F', so that the steam in said chamber will act expansively upon the piston A of enlarged area to drive it forward; but owing to the advanced lead of this piston it will reach the end of its forward stroke and pass the dead-center before the forward stroke of the high-pressure piston A is completed. So soon as the lowpressure piston A has completed its forward stroke its steam-valve H will move and cut off the connection with the steam supply chamber J and open the outward exhaustpassage K. Hence as an exhaust takes place from the high-pressure piston-chamber F into the steam-chamber J the exhaust-steam from the low-pressure piston A is discharged from the engine, while by reason of the relative adjustment of the two pistons the low-pressure exhaust will be closed and the forward movement o f the low-pressure piston A will begin,under the force of steam admitted thereto from the chamber J, before the return- Stroke and exhaust of the high-pressure piston A has ceased. It is evident that this adjustment of the two pistons may be varied without departing` from my invention, and also that the form of the steam-valves H H is immaterial, so that any known form of valve suitable for the purpose may be used as an equivalent therefor in opening and closing the communications between the ports opening into the two piston-chambers and their respective steam-supply and exhaustpassages.

All the working parts of the engine are inclosed in the one casing, so that the engine is not only compact in form, but presents a singularlyneat appearance, and being automatically lubricated by the oil contained in the crank-chamber M, within the casing, will need no attention in this regard, and will remain outwardly clean and free from oil and grime.

By reason of the delivery of the steam from the high-pressure chamber F for use expansively in the low-pressure chamber F (which is made in connection with the intermediate steam-chamber J, by means of which its transmission from the one to the other is effected without interference with a proper relative adjustment of the two pistons.) the engine will work with great'economy as well as elhciency.

I claim as my inventionl. The combination, in a compound singleacting vibrating-piston engine, of pistons of unequal area oscillating in sectorshaped chambers Within the same casing upon separate independent parallel axes mounted in the casing between said chambers, a steamsupply pipe connected with the inlet-port of the piston-chamber of least area, a passage connecting the exhaust-port of said chamber of least area with the pistoni-chamber of larger area, an exhaust-port in said chamber of larger area opening to the atmosphere, valves controlling 'said inlet and exhaust ports, and a crank-shaft mounted parallel with the axes'of the piston and coupled directly to each piston, substantially in the manner and for the purpose herein set forth.

2. A compound vibrating-piston engine having pistons of unequal area oscillating in sector-shaped chambers upon separate independent parallel axes, each chamber being open at its outer end to the atmosphere, in combination with a single crank-shaft mounted parallel with the axes of the pistons between the outer open ends of the piston-chambers and within the same casing, and with coupling-rods connecting said shaft directly with the outer face of each piston, substantially in the lnanner and for the purpose 4herein set forth.

3. The combination, in a compound singleacting vibrating-piston engine, of the casing,

the high and low pressure sector-shaped piston-chambers formed opposite each other in said casing, the intermediate crank-chamber on the one side opening freely into said piston-chambers, the intermediate steam-chamber on the opposite side into which the steam from the high-pressure chamber exhausts and thence passes to the low-pressure chamber, the steam-valves, the crank-shaft in the crankchamber, and the pistons severally oscillating in the piston-chambers upon independent parallel axes mounted in the partition between the piston-chambers, both pistons being coupled4 directly to the one crank-shaft, substantially in the manner and for the purpose herein set forth.

4. The combination, with the piston in a single-acting vibrating-piston engine, of a spring actuated valve opening outward, whereby the piston is relieved from a pressure exceeding that of the highest normalworking-pressure, substantially in the manner and for the purpose herein set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

PETER F. HOLMGREN.

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